Clean-up corrupt empty BTreeFolder2 instances on path import (approved by jm)

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@30236 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/BusinessTemplate.py

@@ -894,6 +894,15 @@ class ObjectTemplateItem(BaseTemplateItem):
             # because they change when we add subobjects
             groups[path] = deepcopy(obj.groups)
           # copy the object
+          if (getattr(aq_base(obj), '_mt_index', None) is not None and
+              obj._count() == 0):
+            # some btrees were exported in a corrupted state. They're empty but
+            # their metadata-index (._mt_index) contains entries which in
+            # Zope 2.12 are used for .objectIds(), .objectValues() and
+            # .objectItems(). In these cases, force the 
+            LOG('Products.ERP5.Document.BusinessTemplate', WARNING,
+                'Cleaning corrupt BTreeFolder2 object at %r.' % (path,))
+            obj._initBTrees()
           obj = obj._getCopy(container)
           try:
             container._setObject(object_id, obj)